http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58668
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |ebotcazou at gcc dot gnu.org
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I think the problem is that ifcvt relies on consistent counting of insns, but
the various functions count different things.
- count_bb_insns counts CALL_INSN and INSN
- flow_find_cross_jump counts in some cases the jump insn (quite complicated
test whether it counts it or not), and doesn't count insns with USE or CLOBBER
PATTERNs
- flow_find_head_matching_sequence counts all CALL_INSN/INSN, including USE and
CLOBBER
- first_active_insn finds what count_bb_insns counts
- last_active_insn (..., TRUE) finds what count_bb_insns except it skips over
USE patterns
I guess best would be to count/skip/etc. the same things consistently, the
problem is that some of the functions have other uses etc.
So, perhaps
1) let count_bb_insns not count insns with USE or CLOBBER PATTERNs
2) perhaps not count any JUMP_INSNs in flow_find_cross_jump if dir_p == NULL
(i.e.
when called from ifcvt)?
3) perhaps not count USE/CLOBBER insns in flow_find_head_matching_sequence if
stop_after is non-zero?
4) perhaps add also skip_use argument to first_active_insn and if TRUE, ignore
USE insns and for both {first,last}_active_insn if skip_use is TRUE, also
ignore CLOBBER insns
5) in find_active_insn_{before,after} ignore USE/CLOBBER insns
and document this properly?
